Axial thermal expansion of ZrO 2 and HfO 2 in the range room temperature to 1400°C

The axial thermal expansion of monoclinic and tetragonal ZrO2 and of monoclinic HfO2 was studied over the temperature range from room temperature to 1400 °C. The linear thermal expansion coefficients were calculated. Thermal expansion along (x 106 per °C) a = 10.31 monoclinic ZrO2, 11.60 tetragonal ZrO2, 9.34 monoclinic HfO2; b = 1.35 monoclinic ZrO2, – tetragonal ZrO2, 2.98 monoclinic HfO2; c = 14.68 monoclinic ZrO2, 16.08 tetragonal ZrO2, 13.10 monoclinic HfO2. Some aspects of the present study, such as anisotropy of thermal expansion and a pretransformation vibrational anomaly, are discussed briefly.